1. Field of the Invention
This invention relates to an information recording method and apparatus for recording an audio and/or visual digital data stream on a disc-shaped recording medium, and a recording medium.
2. Description of the Related Art
Since a hard disc drive has evolved as a peripheral of a personal computer, technical improvement in the hard disc drive has been mainly directed to having access to so-called discrete text data at random with high reliability as promptly as possible.
In keeping up with recent progress in multimedia, there has arisen a need for an HDD and a host system which allow for inexpensive construction of a so-called AV HDD system, whereby an audio visual (AV) digital data stream of, for example, the digital video (DV system SD) standard with a transfer rate of 28.6 Mbps, or the MPEG 2 (Moving Picture Experts Group 2) with the maximum transfer rate of 15 Mbps, as well as random access data other than the AV digital stream, can be handled at will on the disc.
There lacks up to now an information recording device which takes into account variable speed reproduction in case of recording an AV digital data stream, in particular a compressed AV digital data stream, on the disc-shaped recording medium.
Thus, it has been desired to be able to record data so that, by exploiting the properties of the disc-shaped recording medium of reading/writing data in terms of a logical sector as a unit, variable speed reproduction can be readily realized solely by the host-side application software when recording/reproducing the AV digital data stream.
As recording/reproducing medium for an AV digital data stream, a magnetic recording tape is in widespread use. For realizing various sorts of variable-speed reproduction on the AV digital data stream recorded on a tape, control by different types of the hardware is required for reproduction at respective variable speeds.
Thus, for realizing reproduction at various variable speeds, it is indispensable to design the hardware control devices from the outset, such that, in the AV data recording/reproducing apparatus, it has been difficult, in view of the time needed in development, circuit scale or cost to realize the function of optionally varying the variable playback speeds or of continuously varying the variable playback speed.
It is therefore an object of the present invention to provide an information recording method and apparatus and a recording medium in which an AV digital data stream, for example, can be recorded on a disc-shaped recording medium, such as HDD, such as to cope with variable-speed reproduction of the recorded data stream.
It is another object of the present invention to provide a reproducing method and apparatus whereby the playback speed can be set to a continuously variable speed.
In one aspect, the present invention provides an information recording device for recording data on a recording medium having logical sectors as an accessing unit. The recording device includes inputting means for inputting data having a fixed length equal to an integer number times a frame length, and control means for allocating the input data to a predetermined number of contiguous sectors. More specifically, with the recording device of the present invention, data is recorded on the recording medium having a logical sector as an accessing unit. A fixed length of data corresponding to an integer number times the frame length is used as a recording unit. There is provided control means for allocating the recording unit to a minimum number of the logical sectors capable of recording the recording unit in its entirety.
In another aspect, the present invention provides an information recording method including inputting data having a fixed length equal to an integer number times a frame length and allocating the input data to a predetermined number of contiguous sectors. More specifically, with the information recording method of the present invention, data is recorded on a recording medium having a logical sector as an accessing unit. A fixed length of data corresponding to an integer number times the frame length is used as a recording unit. There is provided a control step for allocating the recording unit to a minimum number of the logical sectors capable of recording the recording unit in its entirety.
In yet another aspect, the present invention provides a recording medium on which data having a fixed length equal to an integer number times a frame length has been recorded by being allocated to a predetermined number of contiguous sectors. More specifically, with the recording medium of the present invention, data is recorded on the recording medium having a logical sector as an accessing unit. A fixed length of data corresponding to an integer number times the frame length is used as a recording unit. The recording data is recorded on the recording medium by being recorded in a minimum number of the logical sectors capable of recording the recording unit in its entirety.
According to the present invention, since a defined AV digital data stream can be obtained on simply sending a logical-sector-based read-command from the host side, variable-speed reproduction in AV digital data stream reproduction, such as cue-review, slow, still, fast search, fast accessing or non-linear editing, can be easily realized simply by construction of the host-side application software.
In the reproducing device of the present invention in which an AV digital data stream having a fixed length equal to an integer number times a frame length is recorded on an HDD and reproduced, data corresponding to an integer number of times of the frame length is allocated to a predetermined number of logical sectors of the HDD and data is read out from an optional first sector of the recording unit in various ways by data transfer control which is based only on software to achieve a recording/reproducing function so that the variable-speed reproducing function can be realized more easily than with the conventional method designed in order to achieve the recording/reproducing function by data transfer control by hardware.
In addition, since the variable-speed reproducing speed can be changed freely, it becomes possible to make continuous control of the variable-speed reproducing speed.